Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Commonalities and Differences in the Transcriptional Response of the Model Fungus Saccharomyces cerevisiae to Different Commercial Graphene Oxide Materials
    Laguna-Teno, Felix ; Suarez-Diez, Maria ; Tamayo-Ramos, Juan Antonio - \ 2020
    Frontiers in Microbiology 11 (2020). - ISSN 1664-302X
    biological response - chelating agent - commercial graphene oxide - differential expression - RNA isolation - Saccharomyces cerevisiae - transcriptomics

    Graphene oxide has become a very appealing nanomaterial during the last years for many different applications, but its possible impact in different biological systems remains unclear. Here, an assessment to understand the toxicity of different commercial graphene oxide nanomaterials on the unicellular fungal model organism Saccharomyces cerevisiae was performed. For this task, an RNA purification protocol was optimized to avoid the high nucleic acid absorption capacity of graphene oxide. The developed protocol is based on a sorbitol gradient separation process for the isolation of adequate ribonucleic acid levels (in concentration and purity) from yeast cultures exposed to the carbon derived nanomaterial. To pinpoint potential toxicity mechanisms and pathways, the transcriptome of S. cerevisiae exposed to 160 mg L–1 of monolayer graphene oxide (GO) and graphene oxide nanocolloids (GOC) was studied and compared. Both graphene oxide products induced expression changes in a common group of genes (104), many of them related to iron homeostasis, starvation and stress response, amino acid metabolism and formate catabolism. Also, a high number of genes were only differentially expressed in either GO (236) or GOC (1077) exposures, indicating that different commercial products can induce specific changes in the physiological state of the fungus

    Oxidative and nitric oxide responses in carp macrophages induced by zymosan, MacroGard and selective dectin-1 agonists suggest recognition by multiple pattern recognition receptors
    Pietretti, D. ; Vera-Jimenez, N.I. ; Hoole, D. ; Wiegertjes, G.F. - \ 2013
    Fish and Shellfish Immunology 35 (2013)3. - ISSN 1050-4648 - p. 847 - 857.
    zebrafish danio-rerio - beta-glucan receptor - polymeric immunoglobulin receptor - cyprinus-carpio - atlantic salmon - rainbow-trout - differential expression - dietary beta-1,3-glucan - aeromonas-hydrophila - scavenger receptors
    ß-Glucans are glucose polymers that are found in the cell walls of plants, bacteria, certain fungi, mushrooms and the cell wall of baker's yeast. In mammals, myeloid cells express several receptors capable of recognizing ß-glucans, with the C-type lectin receptor dectin-1 in conjunction with Toll-like receptor 2 (TLR2), considered key receptors for recognition of ß-glucan. In our studies to determine the possible involvement of these receptors on carp macrophages a range of sources of ß-glucans were utilized including particulate ß-glucan preparations of baker's yeast such as zymosan, which is composed of insoluble ß-glucan and mannan, and MacroGard(®), a ß-glucan-based feed ingredient for farmed animals including several fish species. Both preparations were confirmed TLR2 ligands by measuring activation of HEK293 cells transfected with human TLR2 and CD14, co-transfected with a secreted embryonic alkaline phosphatase (SEAP) reporter gene. In addition, dectin-1-specific ligands in mammals i.e. zymosan treated to deplete the TLR-stimulating properties and curdlan, were monitored for their effects on carp macrophages by measuring reactive oxygen and nitrogen radicals production, as well as cytokine gene expression by real-time PCR. Results clearly show the ability of carp macrophages to strongly react to particulate ß-glucans with an increase in the production of reactive oxygen and nitrogen radicals and an increase in cytokine gene expression, in particular il-1ß, il-6 and il-11. We identified carp il-6, that was previously unknown. In addition, carp macrophages are less, but not unresponsive to selective dectin-1 agonists, suggesting recognition of ß-glucans by multiple pattern recognition receptors that could include TLR but also non-TLR receptors. Candidate receptors for recognition of ß-glucans are discussed.
    Carp neutrophilic granulocyes form extracellular traps via ROS-dependent and independent pathways
    Pijanowski, L. ; Golbach, L.A. ; Kolaczkowska, E. ; Scheer, M.H. ; Verburg-van Kemenade, B.M.L. ; Chadzinska, M.K. - \ 2013
    Fish and Shellfish Immunology 34 (2013)5. - ISSN 1050-4648 - p. 1244 - 1252.
    differential expression - net formation - teleost fish - myeloperoxidase - bacterial - immunity - genes - l. - matrix-metalloproteinase-9 - streptococcus
    Neutrophil extracellular traps (NETs) have recently been described as an important innate defense mechanism that leads to immobilization and killing of invading pathogens. NETs have been identified in several species, but the mechanisms involved in NET formation and their role in infection have not been well determined yet. Here we show that upon in vitro stimulation with different immunostimulants of bacterial, fungal or viral origin, carp neutrophilic granulocytes rapidly release NET structures. We analyzed the composition of these structures and the kinetics of their formation by confocal microscopy, by quantifying the levels of extracellular DNA and the release of enzymes originating from neutrophilic granules: myeloperoxidase, neutrophil elastase and matrix metalloproteinase 9 (MMP-9). Profiles of NET release by carp neutrophils as well as their enzyme composition are stimulus- and time-dependent. This study moreover provides evidence for a stimulus-dependent selective requirement of reactive oxygen species in the process of NET formation. Collectively the results support an evolutionary conserved and strictly regulated mechanism of NET formation in teleost fish.
    The Tomato FRUITFULL Homologs TDR4/FUL1 and MBP7/FUL2 Regulate Ethylene-Independent Aspects of Fruit Ripening
    Bemer, M. ; Karlova, R.B. ; Ballester, A.R. ; Tikunov, Y.M. ; Bovy, A.G. ; Wolters-Arts, M. ; Barros Rossetto, P. de; Angenent, G.C. ; Maagd, R.A. de - \ 2012
    The Plant Cell 24 (2012)11. - ISSN 1040-4651 - p. 4437 - 4451.
    mads-box gene - d-glucuronate 4-epimerase - differential expression - 1-aminocyclopropane-1-carboxylate oxidase - agrobacterium-tumefaciens - carotenoid biosynthesis - systems biology - arabidopsis - protein - cloning
    Tomato (Solanum lycopersicum) contains two close homologs of the Arabidopsis thaliana MADS domain transcription factor FRUITFULL (FUL), FUL1 (previously called TDR4) and FUL2 (previously MBP7). Both proteins interact with the ripening regulator RIPENING INHIBITOR (RIN) and are expressed during fruit ripening. To elucidate their function in tomato, we characterized single and double FUL1 and FUL2 knockdown lines. Whereas the single lines only showed very mild alterations in fruit pigmentation, the double silenced lines exhibited an orange-ripe fruit phenotype due to highly reduced lycopene levels, suggesting that FUL1 and FUL2 have a redundant function in fruit ripening. More detailed analyses of the phenotype, transcriptome, and metabolome of the fruits silenced for both FUL1 and FUL2 suggest that the genes are involved in cell wall modification, the production of cuticle components and volatiles, and glutamic acid (Glu) accumulation. Glu is responsible for the characteristic umami taste of the present-day cultivated tomato fruit. In contrast with previously identified ripening regulators, FUL1 and FUL2 do not regulate ethylene biosynthesis but influence ripening in an ethylene-independent manner. Our data combined with those of others suggest that FUL1/2 and TOMATO AGAMOUS-LIKE1 regulate different subsets of the known RIN targets, probably in a protein complex with the latter.
    The banana (Musa acuminata) genome and the evolution of monocotyledonous plants
    Hont, A. D'; Denoeud, F. ; Aury, J.M. ; Kema, G.H.J. ; Dita Rodriguez, M.A. ; Waalwijk, C. - \ 2012
    Nature 488 (2012). - ISSN 0028-0836 - p. 213 - 217.
    in-situ hybridization - sequence count data - dna-sequences - differential expression - maximum-likelihood - gene - rice - diversification - identification - resource
    Bananas (Musa spp.), including dessert and cooking types, are giant perennial monocotyledonous herbs of the order Zingiberales, a sister group to the well-studied Poales, which include cereals. Bananas are vital for food security in many tropical and subtropical countries and the most popular fruit in industrialized countries1. The Musa domestication process started some 7,000 years ago in Southeast Asia. It involved hybridizations between diverse species and subspecies, fostered by human migrations2, and selection of diploid and triploid seedless, parthenocarpic hybrids thereafter widely dispersed by vegetative propagation. Half of the current production relies on somaclones derived from a single triploid genotype (Cavendish)1. Pests and diseases have gradually become adapted, representing an imminent danger for global banana production3, 4. Here we describe the draft sequence of the 523-megabase genome of a Musa acuminata doubled-haploid genotype, providing a crucial stepping-stone for genetic improvement of banana. We detected three rounds of whole-genome duplications in the Musa lineage, independently of those previously described in the Poales lineage and the one we detected in the Arecales lineage. This first monocotyledon high-continuity whole-genome sequence reported outside Poales represents an essential bridge for comparative genome analysis in plants. As such, it clarifies commelinid-monocotyledon phylogenetic relationships, reveals Poaceae-specific features and has led to the discovery of conserved non-coding sequences predating monocotyledon–eudicotyledon divergence
    Diversification of IFNy-inducible CXCb chemokines in cyprinid fish
    Aa, L.M. van der; Chadzinska, M.K. ; Derks, W. ; Scheer, M.H. ; Levraud, J.P. ; Boudinot, P. ; Verburg-van Kemenade, B.M.L. - \ 2012
    Developmental and Comparative Immunology 38 (2012)2. - ISSN 0145-305X - p. 243 - 253.
    trout oncorhynchus-mykiss - chemoattractant i-tac - carpio l. - differential expression - molecular evolution - gene-expression - receptor cxcr3 - early-response - cutting edge - cells
    We earlier identified two CXCL8-like lineages in cyprinid fish, which are functional homologues of the mammalian CXCL8, but with diverged functions. We here investigated whether the carp IFN-¿-inducible CXCb gene, related to the mammalian CXCL9, -10 and -11 chemokines, was subject to a similar diversification. On the zebrafish genome, a cluster of seven CXCb genes was found on chromosome five. Analysis of the promoter of the zebrafish CXCb genes suggests a partially shared, but differential induction. A second CXCb gene, CXCb2, was identified in common carp by homology cloning. CXCb2 is constitutively expressed in immune-related tissues, predominantly in head kidney lymphocytes/monocytes. Interestingly, an induction of CXCb2 gene expression with recombinant carp IFN-¿2 and LPS was observed in macrophages and granulocytes. Finally, difference in sensitivity to LPS, and kinetics of CXCb1 and CXCb2 gene expression during zymosan-induced peritonitis, was observed. These results indicate a functional diversification for cyprinid CXCb chemokines, with functional homology to mammalian CXCL9–11.
    Expression of insulin-like growth factor system components in colorectal tissue and its relation with serum IGF levels
    Vrieling, A. ; Voskuil, D.W. ; Bosma, A. ; Majoor, D.M. ; Doorn, J. van; Cats, A. ; Depla, A. ; Timmer, R. ; Witteman, B.J.M. ; Wesseling, J. ; Kampman, E. ; van't Veer, L.J. - \ 2009
    Growth Hormone & Igf Research 19 (2009)2. - ISSN 1096-6374 - p. 126 - 135.
    factor-i pathway - gene-expression - dietary-protein - differential expression - colon-cancer - receptor - rat - binding - restriction - neoplasia
    Context: The insulin-like growth factor (IGF)-system has been implicated in colorectal tumor carcinogenesis. Although both tumor expression levels and serum concentrations of IGF-system components are related to colorectal cancer risk, it is unknown whether IGF levels in tissue and serum are correlated. Objective: The objective of this study was to determine expression levels of various IGF-system components in different locations of the colorectum, and to investigate whether normal tissue IGF expression levels are correlated with serum IGF-I and IGF-II concentrations. Design: Biopsies from macroscopically normal mucosa at four locations in the colorectum (ascending, transverse, signoid colon, and rectum) and a fasting serum sample were obtained from 48 asymptomatic patients at increased risk of colorectral cancer. Expression levels of IGF-I, IGF-II, IGF-IR, IGF-IIR, and IGFBP-3 messenger RNA (mRNA) in tissue were quantitatively evaluated using real-time RT-PCR. Expression of IGF-IR protein in the ascending colon and rectum tissue specimens was assessed semi-quantitatively by immunohistochemistry. Serum IGF-I and IGF-II concentrations were determined using immunometric assays. Results: With the exception of IGF-IIR, mRNA levels of all the IGF-system components investigated, as well as IGF-IR protein expression, were significantlyhigher in the rectum compared with the ascending colon (p
    Stress and innate immunity in carp: corticosteroid receptors and pro-inflammatory cytokines
    Stolte, H.H. ; Nabuurs, S.B. ; Bury, N.R. ; Sturm, A. ; Flik, G. ; Savelkoul, H.F.J. ; Verburg-van Kemenade, B.M.L. - \ 2008
    Molecular Immunology 46 (2008)1. - ISSN 0161-5890 - p. 70 - 79.
    dna-binding domain - fish glucocorticoid-receptor - early-life stages - cyprinus-carpio - common carp - teleost fish - functional-characterization - mineralocorticoid receptor - differential expression - trypanoplasma-borreli
    The stress hormone cortisol is deeply involved in immune regulation in all vertebrates. Common carp (Cyprinus carpio L.) express four corticoid receptors that may modulate immune responses: three glucocorticoid receptors (GR); GR1, with two splice variants (GR1a and GR1b), GR2 and a single mineralocorticoid receptor (MR). All receptors are expressed as of 4 days post-fertilization and may thus play a critical role in development and functioning of the adult immune system. Immune tissues and cells predominantly express mRNA for GRs compared to mRNA for the MR. Three-dimensional protein structure modeling predicts, and transfection assays confirm that alternative splicing of GR1 does not influence the capacity to induce transcription of effector genes. When tested for cortisol activation, GR2 is the most sensitive corticoid receptor in carp, followed by the MR and GR1a and GR1b. Lipopolysacharide (LPS) treatment of head kidney phagocytes quickly induces GR1 expression and inhibits GR2 expression. Cortisol treatment in vivo enhances GR1a and MR mRNA expression, but only mildly, and cortisol treatment in vitro does not affect receptor expression of phagocytes. Cortisol has no direct effect on the LPS-induced receptor profile. Therefore, an immune rather than a stress stimulus regulates GR expression. Cortisol administered at stress levels to phagocytes in vitro significantly inhibits LPS-induced expression of the pro-inflammatory cytokines tumor necrosis factor alpha (TNF-¿) and interleukin-12 (IL-12) (subunit p35) and of inducible nitric oxide synthase (iNOS) expression.
    In vivo kinetics of cytokine expression during peritonitits in carp: Evidence for innate an alternative macrophage polarization
    Chadzinska, M.K. ; Leon, K.M. ; Plytycz, B. ; Verburg-van Kemenade, B.M.L. - \ 2008
    Developmental and Comparative Immunology 32 (2008)5. - ISSN 0145-305X - p. 509 - 518.
    trout oncorhynchus-mykiss - tumor-necrosis-factor - rainbow-trout - common carp - functional-characterization - differential expression - inflammatory responses - carassius-auratus - molecular-cloning - atlantic salmon
    Despite the discovery of many cytokine genes in fish, knowledge on their functional homology is limited. To enlighten the biological function of inflammation-related mediators, we studied their kinetics of gene expression during peritonitis in carp. Zymosan-induced intraperitoneal influx of phagocytes reached a maximum at 24 h. In peritoneal leukocytes (PTL) up-regulation of IL-1ß, TNF-¿, CXCa, and chemokine receptor CXCR1 preceded this peak. Delayed up-regulation of these genes in the head kidney (HK) indicates emigration of antigen-presenting cells from peritoneum into HK and/or systemic spreading of inflammation. In turn, early increase in expression of anti-inflammatory genes in HK (6 h) precede their up-regulation in the focus of inflammation. In PTL peaks of IL-10 and arginase 2 expression were recorded at 96 and 168 h, respectively. These results give evidence that carp macrophages in vivo differentiate into a continuum of different activation states with innate and alternative activation representing the extremes.
    Biochemical and molecular mechanisms involved in monogenic resistance responses to tomato powdery mildew
    Li Chengwei, ; Bonnema, A.B. ; Che, D. ; Dong, L. ; Lindhout, P. ; Visser, R.G.F. ; Bai, Y. - \ 2007
    Molecular Plant-Microbe Interactions 20 (2007)9. - ISSN 0894-0282 - p. 1161 - 1172.
    salicylic-acid accumulation - disease-resistance - oidium-neolycopersici - differential expression - callose synthase - plant defense - barley lines - cell-death - protein - genes
    The monogenic genes Ol-1, ol-2, and Ol-4 confer resistance to tomato powdery mildew Oidium neolycopersici via different mechanisms. The biochemical mechanisms involved in these monogenic resistances were studied by monitoring through time the association of H2O2 and callose accumulation with hypersensitive response (HR) and papilla formation. Our results showed that H2O2 and callose accumulation are coupled with both Ol-1- and Ol-4¿mediated HR-associated resistance as well as with the ol-2¿mediated papillae-associated resistance. Further, the transcriptomal changes related to these monogenic resistances were studied by using cDNA-amplification fragment length polymorphism. The expression profiling clarified that 81% of DE-TDF (differentially expressed transcript-derived fragments) were up-regulated upon inoculation with O. neolycopersici in both the compatible and Ol-1¿mediated incompatible interactions, though with a difference in expression timing. Of these DE-TDF, more than 70% were not detected in the Ol-4¿mediated resistance, while 58% were expressed in the ol-2¿mediated resistance, generally at later timepoints. Sequence information suggested that most of these DE-TDF are related to genes involved in either basal defense or establishment of compatibility. In addition, DE-TDF (19%) specifically expressed in different incompatible interactions were identified. Expression patterns of some DE-TDF and marker gene GluB suggested that papillae-associated resistance exploits a different defense pathway from that of HR-associated resistance.
    Peroxisome Proliferator-Activated Receptor-alpha-Null Mice Have Increased White Adipose Tissue Glucose Utilization, GLUT4, and Fat Mass: Role in Liver and Brain
    Knauf, C. ; Rieusset, J. ; Foretz, M. ; Cani, P.D. ; Uldry, M. ; Hosokawa, M. ; Martinez, E. ; Bringart, M. ; Waget, A. ; Kersten, A.H. ; Desvergne, B. ; Gremlich, S. ; Wahli, W. ; Seydoux, J. ; Delzenne, N.M. ; Thorens, B. ; Burcelin, R. - \ 2006
    Endocrinology 147 (2006)9. - ISSN 0013-7227 - p. 4067 - 4078.
    ppar-alpha - differential expression - insulin sensitivity - gamma activation - gene-expression - food-intake - rats - diet - hyperglycemia - inhibition
    Activation of the peroxisome proliferator-activated receptor (PPAR)-¿ increases lipid catabolism and lowers the concentration of circulating lipid, but its role in the control of glucose metabolism is not as clearly established. Here we compared PPAR¿ knockout mice with wild type and confirmed that the former developed hypoglycemia during fasting. This was associated with only a slight increase in insulin sensitivity but a dramatic increase in whole-body and adipose tissue glucose use rates in the fasting state. The white sc and visceral fat depots were larger due to an increase in the size and number of adipocytes, and their level of GLUT4 expression was higher and no longer regulated by the fed-to-fast transition. To evaluate whether these adipocyte deregulations were secondary to the absence of PPAR¿ from liver, we reexpresssed this transcription factor in the liver of knockout mice using recombinant adenoviruses. Whereas more than 90% of the hepatocytes were infected and PPAR¿ expression was restored to normal levels, the whole-body glucose use rate remained elevated. Next, to evaluate whether brain PPAR¿ could affect glucose homeostasis, we activated brain PPAR¿ in wild-type mice by infusing WY14643 into the lateral ventricle and showed that whole-body glucose use was reduced. Hence, our data show that PPAR¿ is involved in the regulation of glucose homeostasis, insulin sensitivity, fat accumulation, and adipose tissue glucose use by a mechanism that does not require PPAR¿ expression in the liver. By contrast, activation of PPAR¿ in the brain stimulates peripheral glucose use. This suggests that the alteration in adipocyte glucose metabolism in the knockout mice may result from the absence of PPAR¿ in the brain
    Nutrition and Genes in the Development of Orofacial Clefting
    Krapels, I.P.C. ; Vermeij-Keers, C. ; Müller, M.R. ; Klein, A. ; Steegers-Theunissen, R.P.M. - \ 2006
    Nutrition Reviews 64 (2006)6. - ISSN 0029-6643 - p. 280 - 288.
    growth-factor-alpha - embryonic palatal tissue - retinoid-x-receptor - tgf-beta isoforms - sonic-hedgehog - oral clefts - folic-acid - methylenetetrahydrofolate reductase - craniofacial morphogenesis - differential expression
    Clefts of the lip, alveolus, and/or palate, which are called orofacial clefts (OFC), occur in 0.5 to 3 per 1000 live and stillbirths. The pathogenesis of these congenital malformations remains largely unknown, but evidence is increasing that both nutritional and genetic factors are involved. Unlike genetic factors, nutritional causes can be corrected and may therefore contribute to the prevention of OFC. The goal of this review is to summarize the embryogenesis and genes involved in OFC, and to give an overview of the nutrients and related genes in humans. Improving our knowledge of the role of nutrition, genes, and their interactions in the pathogenesis of OFC may stimulate the development of nutritional interventions for OFC prevention in the future.
    Comparative analysis of the natriuretic peptide precursor gene cluster in vertebrates reveals loss of ANF and retention of CNP-3 in chicken
    Houweling, A.C. ; Somi, S. ; Massink, M.P.G. ; Groenen, M.A.M. ; Moorman, A.F.M. ; Christoffels, V.M. - \ 2005
    Developmental Dynamics 233 (2005)3. - ISSN 1058-8388 - p. 1076 - 1082.
    cardiac chamber formation - sequence-analysis - differential expression - messenger-rna - porcine brain - atrial - cloning - heart - rat - mouse
    We identified and characterized the chicken natriuretic peptide precursor gene cluster and found its organization to be highly conserved compared with the mammalian Nppb-Nppa cluster. However, phylogenetic analysis indicated that the putative chicken natriuretic peptide precursor genes are the homologues of CNP-3 and Nppb, respectively. Comparative expression analysis revealed that, in human, mouse, and rat hearts, Nppb is a novel marker for the differentiating working myocardium. Its expression pattern is strikingly similar to that of Nppa before birth, and diverges only after birth. In contrast, whereas the chicken Nppb gene expression profile resembled that of mammalian Nppb, the CNP-3 gene showed very limited expression in the heart, not resembling the pattern of either Nppa or Nppb. These results show that, in chicken, the Nppa gene has been lost from the natriuretic peptide precursor gene cluster, whereas the CNP-3 gene has been retained
    The action site of carbon dioxide in relation to inhibition of ethylene production in tomato fruit
    Wild, H.P.J. de; Balk, P.A. ; Fernandes, E.C.A. ; Peppelenbos, H.W. - \ 2005
    Postharvest Biology and Technology 36 (2005)3. - ISSN 0925-5214 - p. 273 - 280.
    internal feedback-regulation - 1-aminocyclopropane-1-carboxylic acid - differential expression - gene-expression - higher-plants - acc synthase - apple fruit - pear fruit - biosynthesis - oxidase
    High CO2 can inhibit ethylene production of various fruit. A high level of CO2 (20 kPa) was applied to tomato fruit (Lycopersicon esculentum Mill. cv Aromata) at 18 °C for 5 days. To investigate the primary action site of CO2, we used tomato fruit at a ripening stage where feedback regulation of ethylene production was of limited importance. Feedback reactions were further prevented by a treatment with 1-methylcyclopropene (1-MCP) before exposure to high CO2. Tomatoes with and without 1-MCP pre-treatment were exposed to 0 or 20 kPa CO2. Ethylene production, 1-aminocyclopropane-1-carboxylate (ACC) content and ACC oxidase mRNA abundance were measured after 1, 2 and 5 days exposure to 0 or 20 kPa CO2. High CO2-affected LE-ACO1, LE-ACO3 and LE-ACO4 transcripts differently. Several observations show that high CO2 did not affect the ethylene receptor: (1) CO2 had a much earlier and much stronger inhibitory effect on ethylene production than 1-MCP; (2) CO2 prevented while 1-MCP stimulated ACC accumulation; (3) CO2 prevented the 1-MCP induced decrease of LE-ACO1 abundance, and inhibited the 1-MCP induced decrease of LE-ACO3 abundance. Inhibition of ethylene production together with prevention of ACC accumulation by CO2, both in fruit with and without 1-MCP pre-treatment, points to inhibition at a site before the conversion of ACC to ethylene
    Novel expression pattern of cytosolic gln synthetase in nitrogen-fixing root nodules of the actinorhizal host, Datisca glomerata
    Berry, A.M. ; Murphy, T.M. ; Okubara, P.A. ; Jacobsen, K.R. ; Swensen, S.M. ; Pawlowski, K. - \ 2004
    Plant Physiology 135 (2004)3. - ISSN 0032-0889 - p. 1849 - 1862.
    phaseolus-vulgaris l - transgenic lotus-corniculatus - encoding glutamine-synthetase - differential expression - nucleotide-sequence - medicago-truncatula - gene-expression - corresponding genes - multigene family - alnus-glutinosa
    Gln synthetase (GS) is the key enzyme of primary ammonia assimilation in nitrogen-fixing root nodules of legumes and actinorhizal (Frankia-nodulated) plants. In root nodules of Datisca glomerata (Datiscaceae), transcripts hybridizing to a conserved coding region of the abundant nodule isoform, DgGS1-1, are abundant in uninfected nodule cortical tissue, but expression was not detectable in the infected zone or in the nodule meristem. Similarly, the GS holoprotein is immunolocalized exclusively to the uninfected nodule tissue. Phylogenetic analysis of the full-length cDNA of DgGS1-1 indicates affinities with cytosolic GS genes from legumes, the actinorhizal species Alnus glutinosa, and nonnodulating species, Vitis vinifera and Hevea brasilensis. The D. glomerata nodule GS expression pattern is a new variant among reported root nodule symbioses and may reflect an unusual nitrogen transfer pathway from the Frankia nodule microsymbiont to the plant infected tissue, coupled to a distinctive nitrogen cycle in the uninfected cortical tissue. Arg, Gln, and Glu are the major amino acids present in D. glomerata nodules, but Arg was not detected at high levels in leaves or roots. Arg as a major nodule nitrogen storage form is not found in other root nodule types except in the phylogenetically related Coriaria. Catabolism of Arg through the urea cycle could generate free ammonium in the uninfected tissue where GS is expressed.
    Mechanism of thyroid-hormone regulated expression of the SERCA genes in skeletal muscle: Implications for thermogenesis
    Simonides, W.S. ; Thelen, M.H.M. ; Linden, C.G. van der; Muller, A. ; Hardeveld, C. - \ 2001
    Bioscience Reports 21 (2001)2. - ISSN 0144-8463 - p. 139 - 154.
    sarcoplasmic-reticulum ca2+-atpase - cold-acclimated ducklings - messenger-rna levels - heat-production - postnatal-development - differential expression - uncoupling protein - receptor isoforms - force development - twitch muscle
    Thyroid hormone increases the Ca2+-ATPase activity of the sarcoplasmic reticulum (SR) in skeletal muscle, thereby increasing the energy-turnover associated with Ca2+-cycling during contraction and rest. The fast-muscle isoform of the Ca2+-ATPase (SERCA1) and the slow-muscle isoform (SERCA2a), are encoded by two genes that are transcriptionally regulated by T3. The SERCA1 isoform can be expressed to considerably higher levels than the SERCA2a isoform. The stimulation of transcription of the SERCA1 gene by T3 is mediated by two thyroid hormone response elements, located in the promoter of this gene. The intracellular [Ca2+] can modulate the effect of T3. The increase in SR Ca2+-ATPase activity seen when T3-levels rise above normal, results from the induction of SERCA1 expression in slow muscle fibers. Concomitant high levels of Ca2+-ATPase activity are associated with down-regulation of SERCA2a expression in these fibers. The observed T3-dependent increase in SERCA1 expression and associated Ca2+-ATPase activity will increase the overall metabolic rate of the organism significantly under normal conditions, because of the high average level of contractile activity of slow fibers. Given the rise in serum T3-levels during prolonged cold exposure, these data suggest that fiber-specific stimulation of SERCA1 expression contributes to the thermogenic response in non-shivering thermogenesis. This mechanism may be particularly relevant in larger mammals, which have a relatively high percentage of slow fibers in skeletal muscle, and which need to rely on tissues other than brown fat for the generation of extra heat
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